TGA green-lights 'life-changing' drug to treat SMA

Baby Aviana, who has SMA, has celebrated her first birthday, a rare feat.

A drug that can extend the life of children and adults with spinal muscular atrophy (SMA) has been approved by the Therapeutic Goods Administration and is now commercially available.

Until now, sufferers of SMA had few options, and babies with the most severe form of the genetic disease, SMA1, deteriorated until they couldn't swallow and breathe - usually by nine months of age.

The new treatment, nusinersen (brand name Spinraza), works by causing the body to increase production of a protein called survival motor neurons, which is critical to the function of muscles.

It has been shown to extend and improve the life of babies with SMA1. It is unclear how much the drug will cost, although in the US it can cost $US750,000 ($978,000) for one course of treatment - five to six doses over the first year.

Julie Cini, chief executive of SMA Australia, said the TGA decision was "exciting" news and the next step was to see it listed on the Pharmaceutical Benefits Scheme.

"We've campaigned so hard for this as it shows fantastic promise, but a PBS listing would be the icing on the cake," said Ms Cini, who lost two baby daughters to the disease a decade ago.

"There are 600 sufferers of all ages who will able to access this treatment and to SMA1 babies we can say, 'You're not facing a death sentence anymore'."

SMA is the most common genetic cause of death in children under two years of age. It is caused by a defect in the survival motor neuron (SMN1) gene and occurs in about one in 6000 to 11,000 births.

Bethan and Johnny McElwee's daughter, Aviana, was the first baby in Australia and the ninth in the world to be treated with nusinersen at no cost, via the manufacturer Biogen's extended access program.

She defied the odds by celebrating her first birthday in July. At 16 months old, she is miraculously able to drink a babycino, lift a shampoo bottle, and even beat a cold.

"There's no doubt in my mind that if she wasn't on this phenomenal drug, she'd be gone by now. She's fought off two colds, which in SMA babies can mean the end," said Ms McElwee.

"I would beg on my knees for it to be added to the PBS because it can change lives, it's given Aviana a second chance at life."

The announcement comes as a two-year randomised, double-blinded trial of 122 SMA babies found those given nusinersen were more likely to be alive and show improvements in motor function than babies given placebo.

The drug was so effective the ENDEAR trial was terminated early because it was deemed unethical to keep giving the control babies sham treatment.

The risk of death or the use of permanent assisted ventilation was 47 per cent lower in the nusinersen group than in the control group, found the Phase 3 trial published in the New England Journal of Medicine.

A total of 68 per cent of babies in the control group had died or were on permanent assisted ventilation by the end of the study period compared to 39 per cent of the infants in the nusinersen group.

Fifty-one per cent of the infants in the nusinersen group achieved a motor-milestone: 22 per cent achieved full head control, 10 per cent were able to roll over, 8 per cent were able to sit independently. In the control group, none achieved these milestones.

The drug has been approved in several countries, including the US and Japan, and Biogen said it was working on getting it subsidised on the PBS.

"We will now work closely with the Pharmaceutical Benefits Advisory Committee, the Government and healthcare professionals and hope to ensure that those Australians who could benefit from Spinraza, do," said Christopher Stemple, managing director of Biogen Australia and New Zealand.

The study in the NEJM was sponsored by Biogen and Ionis Pharmaceuticals and involved clinicians and babies at the Sydney Children's Hospital Network and Melbourne Children's Hospital.